Work during the past year has included the following activities: The Japan-Hawaii migrant study has begun to shed light on factors associated with high risk of stomach cancer in Japan and high risk of colon cancer in Hawaii. The application of epidemiologic methods to biochemical research is beginning to lead to an understanding of factors associated with mutagenicity. Study of trends in cancer mortality internationally has revealed a consistent world-wide decrease in stomach cancer. Preliminary analysis of cancer mortality among U.S. Chinese by nativity revealed some evidence of increased risk of colon cancer to the level of U.S. whites, comparable to the findings among Japanese migrants.